revert to use yarn

.github/workflows/test.yml

@@ -13,18 +13,11 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: pnpm/action-setup@v4
-        with:
-          run_install: false
-
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: 22
-          cache: 'pnpm'
+          node-version: 20
+          cache: 'yarn'
 
-      - name: Install dependencies
-        run: pnpm install
-
-      - name: Run tests
-        run: pnpm test
+      - run: yarn install
+      - run: yarn test